I've seen many acts in my travels on the Fringe, but I've never seen anyone quite like Spacedog. Scientists, engineers but above all musicians, their genius lies in their magpie collections of intellectual exotica - picked up seemingly at random, but linked by a shining theme. Joined this year by steampunk favourite Professor Elemental, they fill the Brunswick with their artefacts and contraptions - and fill our minds with spooky, haunting song.

The tenor's set by a mournful opening number, with a sense of an old folk song re-imagined for the modern age. And that blend of old and new proves a recurring theme: Spacedog apply the white heat of now-dated technology to our ageless hopes and fears, invoking an ancient bogeyman as readily as they do the Sputnik.

Jenny Angliss has a strong, pure and sometimes-chilling voice, while sister Sarah strikes a suitably other-worldly pose playing the theremin. The theremin itself is fascinating to watch: with its instantly-recognisable, nerve-jangling electric tone, it's played without physical contact by skilled movement through an electric field. Percussionist Stephen Hiscock also has some unusual tricks up his sleeve (it's the first time I've seen a cymbal played like a violin), and then there are the robots - a singing raven, a possessed ventriloquist's doll, an extraordinary computerised bell-tower.

It could all have been a space-dog's breakfast, but compere Colin Uttley does a good job of holding it all together, aided by the over-arching "Televisor" theme. In the early days of TV, he explained, would-be "Telegazers" would build their own machines - just like the one he'll unveil now on stage. As in all the best episodes of Tomorrow's World, the equipment didn't quite perform, but the ready supply of early-TV trivia still did its job - invoking the excitements and the unknown terrors of a dawning age.

Professor Elemental's guest slot fits nicely into the pattern too; I was sorry not to hear his ever-popular posh rap Cup Of Brown Joy, but I have to admit his quietly horrid number about a haunted toy-box was a much better match for the overall tone. At times, in fact, it all got too dark, and a couple of Spacedog's pieces cross the line from sinister into out-and-out disturbing. But don't be put off: there's plenty to enjoy, on this weird and jagged border-line between art and science.